WO2016180565A1 - End effector of a wafer handling system, and wafer handling system - Google Patents

Abstract

The invention relates to an end effector having an integrated prealigner which preferably comprises a movable tongue having a rotational disk.

Description

ENDFFECTOR OF A WAFER HANDLING SYSTEM AS WELL

WAFER HANDLING SYSTEM

description

Field of the invention

The invention relates to the end effector of a

Wafer handling system. In particular, the invention relates to a wafer handling system comprising an end effector by means of which a wafer can be transferred from a FOUP to a wafer handling system

Processing station or between different

Processing stations can be transported. The

The invention further relates to a method for transporting a wafer using an inventive

Endeffectors.

Background of the invention

In plants of the semiconductor industry, ie in particular in lithography and metrology systems or systems for

Processing of wafers is often a so-called

Prealignment, so an alignment of the wafer transported into the plant required. As a rule, the wafer has at least one marking for this purpose and can thus have an optically controlled handling device

be aligned, both rotational and in its horizontal position. Further, in some cases, vertical alignment of the wafer is also possible

required. From the practice known plants are therefore provided with a so-called Prealigner, which as a separate

Process station can be considered, in which the wafer is aligned before further process steps.

Disadvantages are the installation space required for this purpose and the longer process time associated with the realignment of the wafer.

Object of the invention

The invention is based on the object, at least reduce the disadvantages of the prior art mentioned.

Summary of the invention

The object of the invention is already by a

End effector according to claim 1 and by a

 Endeffector comprehensive wafer handling system according to claim 6 and by a method for transporting a wafer using an end effector according to claim 9 solved. Preferred embodiments and further developments of

Invention are the subject of the dependent claims

remove .

The invention relates to the end effector of a

Wafer handling system. An end effector is the last element of a kinematic chain for transporting and processing the wafer, which is responsible for gripping and holding the wafer during wafer transport. The end effector is usually responsible for removing the wafer from a storage box and placing it on the first processing station, or vice versa, or to pick up the wafer from a workstation and place it on another workstation.

For this purpose, the wafers to be processed are generally available in a storage box designed as a FOUP, that is to say a front opening unified pod. It is a forwardly open unit container, in which the wafers are arranged in a plurality of slots.

The end effector includes a wafer holder for receiving the wafer. This wafer holder is usually arranged on a movable carrier and is guided by means of the carrier under the wafer in order to grip the wafer can. The wafer holder typically includes one or two fingers that grip under the wafer, but other shapes are also used to grip the wafer holder of the wafer. The often used wafer holders fix the wafer by means of negative air pressure. There is also

Wafer holder, which electrostatically or mechanically

work, for example, work with edge grabbing.

According to the invention, the wafer holder comprises a

integrated prealigner. Under a prealigner according to the invention is

in particular a device understood, by means of which the wafer relative to the fingers of the wafer holder or relative to a carrier of the end effector is relatively movable. The position of the wafer on the wafer holder can thus be changed by the end effector itself in order to align the wafer in the course of removal from the FOUP can.

The alignment can be at least partially during the transport of the wafer from the FOUP to the first

Processing station done.

By the end effector with integrated prrealignment can so on another prealigner in the plant itself

be waived. Further, if necessary, the process time can also be shortened, in particular if the realignment takes place at least partially during the transport of the wafer to the processing station. In a preferred embodiment of the invention, the prealigner comprises a tongue which is movable between the fingers of the wafer.

So can the prealigner between the fingers of the

Get wafer holders from below to the wafer.

When placing the wafer on a support station

(For example, a wafer chuck), which as the first

Processing station can be formed, the tongue can be moved out at least partially between the fingers of the wafer holder to the rear, so that in the

Auflagestation recesses only for the fingers of the Wafer holders must be provided. Since previously the tongue can act as support for the wafer, it is conceivable to make the fingers of the wafer holder and thus also the necessary recesses on the investment station narrower.

The tongue is also vertically movable in one embodiment of the invention to the wafer or another

Prealigner element, which is connected to the tongue to be able to lift.

Next is also conceivable, the tongue for aligning

to move in rotation. It is also conceivable, however, an embodiment of the invention in which the tongue is designed to be movable not only in a horizontal direction, but in which this only another element of the prealigner, in particular a turntable wears.

Preferably, the prealigner comprises a turntable over which the wafer can be rotationally aligned. Preferably, the turntable is liftable to lift the wafer from the fingers of the wafer holder and rotate. A liftability of the turntable can be provided both on the turntable itself, ie via an adjusting element, which is integrated in the turntable, as well as by means of a vertically movable tongue on which the turntable is arranged.

The prealigner thus exists in a preferred one

Embodiment of the invention of tongue and turntable. It is understood that the turntable may have any shape that allows to rotate the raised wafer. The turntable must therefore not be circular.

The invention further relates to a

Wafer handling system, which the previously described

Includes an end effector with integrated prealigner and a camera for measuring the wafer picked up by the end effector.

The camera can be designed, for example, as a line or area camera.

In one embodiment of the invention, the

Measurement of the wafer by means of a line camera during removal from the FOUP. An exact measurement of the

Wafers can be realized in a very simple way and also takes place while it is being transported by the end effector anyway. There are others, of course

Positions for the line camera for measuring the wafer possible. The invention further relates to a method, wherein the above-described end effector is used and wherein the wafer by means of the end effector on a

Storage station, which in particular as the first

Processing station is formed, is transported. In this case, the wafer is preferably aligned at least rotationally, in particular by means of a turntable which is part of the prealigner described above. The wafer can also be partly aligned with the end effector itself. In particular, it is provided that prealigner and end effector cooperate in aligning the wafer. The end effector typically includes a wafer holder carrier. The carrier may be rotatable along a vertical axis, whereby the end effector can transport the wafer by rotation. Next, the end effector can also be linear in one

horizontal direction to be movable, about the

Wafer holder in the FOUP or in the first Auflägestation retract. This linear movement can also be achieved by means of a carrier which can be moved linearly on the carrier.

Thus, in the horizontal plane over the

Linear motion or other movement of the end effector of the wafer to be aligned. Furthermore, in the context of the rotational movement by a change of the angle a

 Alignment also possible perpendicular to this linear direction.

Next, the end effector can be part of a

Automation device, such as part of a robot to be. Using these, the entire end effector can be moved linearly or rotationally. The prealigner therefore only needs the wafer, as provided in one embodiment of the invention

rotational alignment, while further alignment is via movement of the end effector itself.

It is also conceivable, in particular, the vertical

to use movable tongue to the wafer in a linear direction on the fingers of the wafer holder

make out.

Further, it is possible to use the prealigner during transport and / or surveying of the wafer to vertically align the wafer. In particular, by means of the prealigner, the deflection of the wafer can be reduced, which is also interesting for applications in which the depth of field plays a role, since the relevant

Sensors often have only a shallow depth of field.

Brief description of the drawings

The subject matter of the invention will be explained in more detail below with reference to schematically illustrated exemplary embodiments with reference to the drawings, FIGS. 1 a to 2h.

FIGS. 1 a to 1c show an end effector

integrated prealigner in different positions.

FIGS. 2a to 2h show a wafer handling system which includes an end effector, a camera, a FOUP and a

Staging station includes, in various process steps. FIGS. 3a and 3b show an embodiment of an end effector with a pivotable tongue.

Detailed description of the drawings

FIGS. 1 a to 1c show a schematic,

Perspective view of the end effector 1 with an integrated prealigner. The end effector 1 comprises, as can be clearly seen in particular in FIG. 1 a, a carrier 3, which comprises a wafer holder 2 for receiving a wafer.

The wafer holder 2 comprises two fingers 4 arranged on the carrier, which serve to receive and hold the wafer. This can be done for example via integrated channels in the fingers with a suction device.

The carrier 3 is movable in this embodiment of the invention both in a horizontal horizontal direction and in rotation about a vertical axis. Preferably, the carrier is also linearly movable in the vertical direction, approximately to approach the various slots of the FOUP. According to the invention, the end effector 1 comprises a

integrated prealigner, which in this

Embodiment one between the fingers 4 of the

Wafer holder arranged tongue 5 and a front of the tongue 5 arranged turntable 6 includes.

As shown now in Fig. Lb, the tongue 5 and thus also the turntable 6 can be moved vertically upwards. An arranged on the turntable 6 wafer would now raised and could then by means of

Turntable, as shown in Fig. Lc, are moved relative to the fingers of the wafer holder.

After completion of the so-performed rotational alignment of the wafer, as shown in Figure ld, the tongue 5 is again moved vertically downwards, whereby a on the

Turntable 6 lying wafer is placed back on the fingers 4 of the wafer holder.

It is understood that this vertical movement can be realized in other embodiments of the invention via a turntable, which itself moved vertically is. It is also conceivable to let the tongue perform a pivoting movement to lift the turntable vertically.

Furthermore, it is also conceivable that the tongue can also be pivoted in the horizontal plane in order to lateralize the wafer with respect to the fingers of the wafer holder

to align.

Further, the tongue is preferably retractable linearly in the carrier. This is shown in Fig le.

The retractable tongue serves to reduce the size of the recesses for the end effector on the storage station and to increase the contact surface of the wafer and thus to reduce its deflection. Especially at

Applications in which the depth of field of a

However, the tongue does not need to be retractable. Fig. Le shows that the tongue 5 can be retracted linearly to the rear in the carrier 3 and thus also the

Turntable between the fingers 4 of the wafer holder

withdraws. The tongue is moved vertically to a position below the fingers 4, so that the turntable 6 has no contact with the underside of the wafer.

A resting wafer now sits only on the fingers 4 of the wafer holder. This is special

provided to drive the wafer by means of the wafer holder in a processing station, in which recesses must be present for receiving the fingers 4 of the wafer holder. However, it is also conceivable that the linear movement of the tongue 5 is used to align the wafer in the context of a prealigning with respect to the fingers 4 of the wafer holder.

2a to 2h show a schematic view of a wafer handling system, which, as shown in particular in FIG. 2a, comprises the previously described end effector 1 and a FOUP, from which wafers are removed from the end effector 1 and transferred to a support station 8.

For this purpose, the carrier 3 of the end effector is rotatable along a vertical axis. Further, the carrier is also linear in the vertical direction and linear in the horizontal direction, in the direction of the fingers of the prealigner movable.

The support station 8, in which, for example, a first processing step takes place, comprises as grooves

configured recesses 9, which are the fingers of

Pick up wafer holders when depositing.

Furthermore, the handling system comprises a camera 10, with which a wafer resting on the wafer holder

can be measured.

As shown in Fig. 2b, a wafer 11 is moved out of the FOUP 7 by a movement of the carrier.

For this purpose, the carrier 3 moves the fingers of the wafer holder under a wafer arranged in an insert of the FOUP 7. The fingers of the wafer holder are then lifted by means of the carrier 3 and the wafer is replaced by a

Linear movement of the carrier 3 moved out of the FOUP and arrives in the position shown here.

Then, as shown in Fig. 2c, the wafer is measured by means of the camera 10. It is in this

Embodiment of the camera 10 to a

Area camera. The cone shown in the picture below

Camera 10 represents the field of view of the camera. It is understood that a not garaged here lighting

can be used to capture the image

provide needed light.

It is also conceivable, however, to use a line camera, by means of which the wafer is measured during its movement out of the FOUP 7 or during another relative movement of the beetle to the line scan camera.

Then, the wafer 11, as shown in Fig. 2d and Fig. 2e, by a rotational movement of the support 3 to, for example, aligned by about 180 ° in the direction of the support station 8. The angle depends on the concrete

Configuration of the handling system and can also have a different value.

While this moving can simultaneously, as under

With reference to FIGS. 1 a to 1 d, the wafer 11 is aligned on the wafer holder by means of the prealigner. However, it is also conceivable that the realignment takes place in a separate process step, for example after the

Measurement by means of the camera (shown in Fig. 2c) or only after the wafer 11 (as shown in Fig. 2e) in the direction of the receiving station 8 shows.

Fig. 2f shows how the wafer 11 now has a

Linear movement of the carrier 3 is placed on the support station 8.

In this case, the tongue 5 is moved in this embodiment to the rear, so that the area between the fingers of the wafer holder is released and for the support station 8, the tongue 5 must have no or only a smaller recess.

Within the scope of the prealignation of the wafer, it is now conceivable, via the linear movement of the carrier 3 for

Receiving station 8, the wafer 11 in this horizontal

To align direction.

Further, as shown in FIGS. 2d and 2e

Rotational movement of the end effector, the position of the wafer can also be aligned perpendicular to this linear movement. The prealigner would be necessary in this case only for the rotational alignment of the wafer 11.

FIG. 2 g shows how the end effector 1 was moved out of the support station 8 by moving the carrier 3 down and a linear movement. The end effector 1 is now rotated again, as shown in Fig. 2h, so that the fingers of the wafer holder point in the direction of the FOUP. The end effector 1 is now ready to drive out another wafer from the FOUP 7.

Instead of the linearly extendable tongue, a rotatable tongue can also be used: Before depositing the wafer on the deposition station, the tongue is lowered between the fingers and then the finger is turned sideways. The advantage lies in a simpler technical design, the disadvantage in an increased lateral space requirement.

Such an embodiment is shown in Fig. 3a and Fig. 3b.

As shown in Fig. 3a, the tongue 5 can be moved down between the fingers 4 of the end effector 1.

Then, as shown in Fig. 3b, the tongue 5 is pivoted on the carrier 3 to the side. Also with this

 Embodiment, the tongue 5 comprises a turntable. 6

Furthermore, according to one not shown in the drawings

The wafer is picked up only by the tongue, rotated on the tongue and placed on a storage station. The tongue need not perform any vertical movement in the end effector, since no relative movement between the tongue and fingers is necessary.

By integrating the prealignment in the end effector, the construction of plants of the semiconductor industry, ie especially in lithography and metrology facilities or facilities for processing of wafers. Furthermore, process times can be shortened.

LIST OF REFERENCE NUMBERS

1 end effector

2 wafer holders

3 carriers

 4 fingers

 5 tongue

 6 turntables

7 FOUP

 8 AuflägeStation

9 recess

10 camera

 11 wafers

Claims

Claims : End effector (1) of a wafer handling system, comprising a wafer holder (2) for receiving a wafer (11), characterized in that the wafer holder (2) comprises an integrated prealigner. End effector according to claim 1, characterized in that the prealigner comprises a tongue (5) which is arranged in particular between fingers of the wafer holder. End effector according to claim 2, characterized in that the tongue (5) is movable, in particular linearly movable, or pivotable. End effector according to one of the preceding claims, characterized in that a wafer is rotatable by means of the prealigner, in particular by means of a turntable (6). End effector according to claim 4, characterized in that the prealigner a vertically movable  Wafer support surface comprises, in particular designed as a vertically movable turntable (6). Wafer handling system comprising an end effector (1) according to any one of the preceding claims and a camera (10) for measuring a picked-up wafer (11). Wafer handling system according to claim 6, characterized in that the camera (10) ^¬ as surfaces or line camera is formed. Wafer handling system according to one of the preceding Claims, further comprising a FOUP (7) and a storage station (8), wherein a wafer (11) by means of the end effector (1) from the FOUP (7) on the Storage station (8) is transportable. A method for transporting a wafer using an end effector according to any one of the preceding Claims, wherein the wafer (11) by means of Endeffectors (1) on a storage station (8) is transported. A method according to claim 9, characterized in that the wafer (11) is rotationally aligned, in particular by means of a turntable (6) of the Prealigners. Method according to one of the preceding claims, characterized in that the wafer (11) is in a horizontal plane is aligned. A method according to claim 11, characterized in that the wafer (11) is aligned by means of the prealigner and / or by means of a movement of the end effector (1) in a horizontal plane. 13. The method according to any one of the preceding claims, characterized in that the wafer (11) is aligned vertically by means of a prealigner. 14. The method according to any one of the preceding claims, characterized in that the wafer (11) is measured in the removal from a FOUP (7), in particular by means of a line scan camera. 15. The method according to any one of the preceding claims, characterized in that the wafer (11) during transport from a FOUP (11) to a  Storage station (8) and / or when depositing on a storage station (8) and / or during transport between two storage stations and / or during transport from a storage station to a FOUP is aligned by means of the prealigner.